Method and apparatus for providing power to a network interface device via telephone lines

RELATED APPLICATIONS

p-0002The present application is related to and hereby claims the priority benefit of commonly-owned U.S. Provisional Patent Application No. 60/793,090, entitled “NETWORK INTERFACE DEVICE” filed Apr. 18, 2006, by James T. Schley-May and Michael Henderson.

FIELD OF THE INVENTION

p-0003Embodiments of the invention generally relate to telecommunication systems used to provide broadband access. More particularly, an aspect of an embodiment of the invention relates to providing power to network interface devices.

BACKGROUND OF THE INVENTION

p-0004Typically, telecommunication systems that provide broadband access to residential customers contain a residential gateway which consists of an xDSL (any type of digital subscriber line generally communicated over copper lines) modem or xPON (any type of passive optical network generally communicated over optic fibers) interface combined with various local area networking (LAN) technologies to enable sharing the broadband access with other computers or devices within the residence. Wireless local area network standards and home phone line networking (HPNA) are examples of such LAN technologies. In addition, some telecommunication systems may provide a voice-over-internet-protocol (VOIP) feature to allow telephone calls via the broadband link. Some systems may, in addition to broadband access sharing, need to distribute broadband media content such as video streams into various locations within the residence.

p-0005Typically the residential gateway is located inside the house. However, it is desirable to locate the residential gateway at the network interface device (NID) outside the house. A NID is the point of demarcation between the Unbundled Network Element (UNE) loop and the end user's inside wire. Reasons for desirability of locating the residential gateway at the NID include to provide simplified installation wiring and to eliminate the need to have the user home when the bulk of installation occurs. Further, as fiber to the neighborhood rolls out, integration will be easier if the active electronics are already present at the NID. Also, installation practices can be merged between xPON and xDSL systems such that the primary network termination is the mere difference.

p-0006However, a significant problem in trying to locate the residential gateway at the NID is the problem of providing power. There is often no external source of Alternating Current (AC) power accessible at the NID location. Consequently, powering from inside the house is the general viable option.

p-0007Current schemes for providing power to the NID or other equipment not located close to conventional power sources involves the installation of separate wires between the NID or other equipment and the conventional power sources. These schemes often require creating holes in the exterior and/or interior walls of buildings. Additional labor and material expense is associated with this additional separate wiring.

SUMMARY OF THE INVENTION

p-0008Various methods, apparatuses, and systems are described in which a residential gateway is located at the network interface device and is powered with a power source inside the residence. In one embodiment, an apparatus includes a network interface device (NID) located outside a residence and a power supply unit located inside the residence. The power supply unit has an electrical isolation component and one or more ports that couple via a first phone line and a second phone line to the NID to provide isolated direct current (DC) power to the NID.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0009The drawings refer to embodiments of the invention in which:

p-0010<figref idrefs="DRAWINGS">FIG. 1</figref> shows a block diagram of an embodiment of a central office containing a Digital Subscriber Loop Access Multiplexer sending communications across an Unbundled Network Element (UNE) loop to a network interface device.

p-0011<figref idrefs="DRAWINGS">FIG. 2</figref> shows a block diagram of an embodiment of providing DC power to a network interface device via telephone lines.

p-0012<figref idrefs="DRAWINGS">FIG. 3</figref> shows a block diagram of another embodiment of providing DC power to a network interface device via telephone lines.

p-0013<figref idrefs="DRAWINGS">FIG. 4</figref> shows a block diagram of another embodiment of providing DC power to a network interface device via telephone lines.

p-0014<figref idrefs="DRAWINGS">FIG. 5</figref> shows a method for providing DC power to a network interface device via telephone lines.

p-0015While the invention is subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. The invention should be understood to not be limited to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DISCUSSION

p-0016In the following description, numerous specific details are set forth, such as examples of specific signals, named components, connections, number of windings in a transformer, example voltages, etc., in order to provide a thorough understanding of the present invention. It will be apparent, however, to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well known components or methods have not been described in detail but rather in a block diagram in order to avoid unnecessarily obscuring the present invention. The specific details set forth are merely exemplary. Further specific numeric references such as a first converter, may be made. However, the specific numeric reference should not be interpreted as a literal sequential order but rather interpreted that the first converter is different than a second converter. Thus, the specific details set forth are merely exemplary. The specific details may be varied from and still be contemplated to be within the spirit and scope of the present invention. The term coupled is defined as meaning connected either directly to the component or indirectly to the component through another component.

p-0017In general, various apparatuses and methods are described in which a network interface device (NID) is powered by an isolated DC power source. In one embodiment, an apparatus includes a NID located outside a residence and a power supply unit located inside the residence. The power supply unit has an electrical isolation component and one or more ports that couple via a first phone line and a second phone line to the NID to provide isolated DC power to the NID. The first phone line includes one wire from a first ring/tip pair and the second phone line includes one wire from a second ring/tip pair that couples between the power supply unit and the NID. The first and second phone lines provide two voice circuits to the residence and simultaneously provide a power circuit for the NID.

p-0018<figref idrefs="DRAWINGS">FIG. 1</figref> shows a block diagram of an embodiment of a central office containing a Digital Subscriber Loop Access Multiplexer (DSLAM) sending communications across an Unbundled Network Element (UNE) loop to a network interface device (NID). A NID is the point of demarcation between the Unbundled Network Element (UNE) loop and the end user's inside wire. The DSLAM <b>102</b> sends communications to the NID <b>104</b> located outside a residence <b>110</b>. The NID <b>104</b> includes a residential gateway <b>106</b> that routes various types of communications, such as data, voice, and video, into the residence <b>110</b>. The communications may be sent to a computer <b>112</b>, television <b>114</b>, phone <b>116</b>, and phone <b>120</b>.

p-0019Voice data is sent from the residential gateway <b>106</b> located in the NID <b>104</b> to the phone <b>116</b> and the phone <b>120</b> via a first phone line <b>118</b> and a second phone line <b>122</b>, respectively. A power supply unit (PSU) <b>130</b> located inside the residence <b>110</b> couples via the first phone line <b>118</b> and the second phone line <b>122</b> to the NID <b>104</b> to provide isolated (non-grounded) DC power to the NID <b>104</b>. The PSU <b>130</b> is located close to both a conventional power source such as a <b>120</b> volt alternating current (AC) outlet and telephone wiring. The PSU <b>130</b> converts the energy from the conventional power source into a form compatible with low voltage, low current telephone wiring already present in the residence <b>110</b>. In order to avoid induction or conduction of electrical noise into the telephone wiring of the residence <b>110</b>, the outgoing power conductors of the PSU <b>130</b> and NID <b>104</b> are not connected to earth ground.

p-0020In one embodiment, the first phone line <b>118</b> has two wires in the form of a ring/tip pair. The second phone line <b>122</b> also has two wires in the form of a ring/tip pair. An isolated DC signal is sent from the PSU <b>130</b> to the NID <b>104</b> via one wire from the first phone line <b>118</b>. The NID <b>104</b> returns the isolated DC signal to the PSU <b>130</b> via one wire from the second phone line <b>122</b>. Thus, the first and second phone lines <b>118</b> and <b>122</b> provide two voice circuits to the residence <b>110</b> and simultaneously provide a power circuit for the NID <b>104</b>.

p-0021The design for the NID <b>104</b> allows power to be delivered from an indoor plug-in device that is located within a residence <b>110</b> to power the NID <b>104</b> or other outdoor devices using telephone wires that are simultaneously being used for telephone service. Thus, the design for the NID <b>104</b> allows DC powering over two pairs of telephone lines while at the same time leaving them available for phone service. This telephone signal compatible DC power scheme enables the market in that having to install a new pair to feed power would be costly, or alternately, giving up one of the two existing pairs to feed power would reduce functionality. Note, some other outdoor mounted communication products, which use power for operation, may require a separate installation of wires leading from the outdoor device to a source of power. The design allows minimizing the expense of installing devices located external to a residence while providing service to their customers. This design does not require a separate installation of wires leading from the outdoor device to a source of power. The design allows borrowing one line from each of two tip/ring pairs and injecting power into the two lines at one location, recovering the power at a distant location from those two telephone lines. The design provides two voice circuits AND a non-interfering power circuit over the same two pairs of telephone lines.

p-0022The design allows equipment connected to home telephone wiring but without access to other standard AC electrical power sources to receive power through home telephone wiring while retaining use of the same wires for telephone use. The residence <b>110</b> may be any type of building, dwelling, or structure that has an internal power source and phone service.

p-0023<figref idrefs="DRAWINGS">FIG. 2</figref> shows a block diagram of an embodiment of providing DC power to a network interface device via telephone lines. The block diagram <b>200</b> includes a network interface device (NID) <b>202</b> located outside a residence and a power supply unit (PSU) <b>204</b> located inside the residence. The NID <b>202</b> performs interface functions, such as code conversion, protocol conversion, and buffering, required for communications to and from a network. The NID <b>202</b> converts each device protocol into a common transmission protocol.

p-0024The PSU <b>204</b> has an electrical isolation component (EIC) <b>206</b>, an output port <b>207</b> and an input port <b>208</b> that couples via a first phone line <b>210</b> and a second phone line <b>214</b> to the NID to provide isolated DC power to the NID <b>202</b>. The first phone line <b>210</b> includes one wire <b>212</b> from a first ring/tip pair and the second phone line <b>214</b> includes one wire <b>216</b> from a second ring/tip pair that couples between the power supply unit <b>204</b> and the NID <b>202</b>. The first and second phone lines provide two voice circuits to the residence and simultaneously provide a power circuit for the NID <b>202</b>.

p-0025In one embodiment, the PSU <b>204</b> includes the EIC <b>206</b> and output port <b>207</b> that sends an isolated DC signal to the NID <b>202</b> via the wire <b>212</b> of the first phone line <b>210</b> and the input port <b>208</b> that receives the isolated DC signal returning to the PSU <b>204</b> via the wire <b>216</b> of the second phone line <b>214</b>. To avoid induction or conduction of electrical noise into the telephone wiring of the residence, the power conductors of the PSU <b>204</b> are not connected to earth ground. To avoid similar problems with electrical noise, the power input circuitry of the NID <b>202</b> at the residential location is also not connected to earth ground.

p-0026The electrical isolation component <b>206</b>, such as a capacitor, a transformer, or a rectifier, generates isolated DC power across the wire <b>212</b> of the first phone line <b>210</b> (first ring/tip pair) and the wire <b>216</b> of the second phone line <b>214</b> (second ring/tip pair) that generates the isolated DC signal with less than 5 volt DC bias between each wire in the first ring/tip pair and also between each wire in the second ring/tip pair. Furthermore, the isolated DC signal generates approximately no AC impedance change between each wire in the first ring/tip pair and also between each wire in the second ring/tip pair. Thus, the power conducted through the two phone line network can be used to power equipment on the same two phone lines without interfering with the operation of those pieces of equipment.

p-0027In one embodiment, as illustrated in <figref idrefs="DRAWINGS">FIG. 2</figref>, power is provided to the residential gateway located at the NID <b>202</b> via the existing phone lines by the PSU <b>204</b> located inside the residence. Thus, two pairs of existing phone lines are used. This is accomplished, in part, by placing active electronics in the NID <b>202</b>, and by having the internal power supply feeding a single wire from each of the two pairs of phone lines. Power may be supplied over the existing phone lines that can still be used for plain old telephone service (POTS) devices such as POTS telephones <b>220</b>, <b>222</b>, <b>224</b>, and <b>226</b>. Furthermore, the bidirectional communication may occur between the residential gateway and PSU <b>204</b>. The residence with the residential gateway may be any type of building, dwelling, or structure that has an internal power source and phone service.

p-0028Telephones and other POTS devices, such as fax machines, answering machines, and analog modems, may also couple to the phone lines <b>210</b> and <b>214</b>. Optional HPNA devices may also couple to the phone lines <b>210</b> and <b>214</b> via a filter.

p-0029Note, the above embodiments utilize direct current (DC) to conduct power from the PSU <b>204</b> to the NID <b>202</b>, but alternating current (AC) power sources can be used as well. When the equipment using the telephone wire pairs for signaling does not require direct current connectivity, the signals can be coupled onto the pairs using non-ground referenced output devices, such as opto-couplers or transformers.

p-0030<figref idrefs="DRAWINGS">FIG. 3</figref> shows a block diagram of another embodiment of providing DC power to a network interface device via telephone lines. The block diagram <b>300</b> includes a network interface device (NID) <b>302</b> located outside a residence or building and a power supply unit (PSU) <b>330</b> located inside the residence or building. The PSU <b>330</b> has an electrical isolation component (EIC) <b>334</b>, an output port <b>331</b> and an input port <b>332</b> that couples via a first phone line <b>312</b> and a second phone line <b>318</b> to the NID <b>302</b> to provide isolated DC power to the NID <b>302</b>. The first phone line <b>312</b> includes one wire <b>314</b> and one wire <b>316</b> that form a first ring tip pair. The second phone line <b>318</b> includes one wire <b>320</b> and one wire <b>322</b> that form a second ring tip pair. The wire <b>316</b> from the first ring/tip pair and the wire <b>322</b> from the second ring/tip pair couple between the PSU <b>330</b> and the NID <b>302</b> to provide isolated DC power to the NID <b>302</b>. The wire <b>314</b> from the first phone line <b>312</b> and the wire <b>320</b> from the second phone line <b>318</b> are not connected to the NID <b>302</b>. The first and second phone lines provide two voice circuits to the residence and simultaneously provide a power circuit for the NID <b>302</b>.

p-0031The PSU <b>330</b> includes a first converter <b>342</b> that receives AC input voltage, such as 110 volt (V) or 120V household, and converts that voltage to a ground referenced DC voltage such as 15V DC. The first converter <b>342</b> couples to a controller <b>336</b> and a battery charger <b>340</b>. The battery charger <b>340</b> couples to a battery <b>338</b> that couples to the controller <b>336</b> as illustrated in <figref idrefs="DRAWINGS">FIG. 3</figref>. The battery <b>338</b> may be a 12 volt battery. The EIC <b>334</b> includes a second converter <b>335</b> that couples to the controller <b>336</b>. The second converter <b>335</b> receives a ground referenced DC voltage from the controller <b>336</b> and then converts that voltage to the supplied isolated DC voltage, which may be 29V DC. The isolated DC voltage needs to be less than or equal to 30V to meet safety requirements for ungrounded voltage within a residence or building. The isolated DC voltage also needs to be sufficiently close to 30V to withstand voltage drops proportional to the distance across the phone lines for the power circuit that provides power to the NID <b>302</b>.

p-0032The controller <b>336</b> selects between the battery <b>338</b> and the first converter <b>342</b> to provide the input ground referenced DC voltage of the second converter <b>335</b>. The controller <b>336</b> selects the battery <b>338</b> if the AC voltage supplying the first converter <b>342</b> is not available.

p-0033As previously discussed, to avoid induction or conduction of electrical noise into the telephone wiring of the residence or building, the outgoing power conductors of the PSU <b>330</b> are not connected to earth ground. Because current leaves the PSU <b>330</b> on the wire <b>316</b> of the first phone line <b>312</b> and returns on the wire <b>322</b> of the second phone line <b>318</b>, each telephone wire pair experiences no imposed current between the two wires which comprise one telephone pair. An imposed voltage of less than 5V may be developed which depends on the length of wires <b>316</b> and <b>322</b>. Subscriber line interface circuits (not shown) that use line <b>312</b> and <b>318</b> can be made to compensate or null out the imposed voltage so as to not effect operation. For the same reason, no electrical impedance change is perceivable between the wires of any one telephone pair; allowing telephone use on each pair to proceed as if the power distribution scheme was not present.

p-0034To avoid similar problems with electrical noise, the power input circuitry of the NID <b>302</b> at the residential location is also not connected to earth ground. The power received at an input <b>305</b> of an electrical isolation component (EIC) <b>304</b> of the NID <b>302</b> is converted by a third converter <b>306</b> into power sources that may be referenced to earth ground (output <b>307</b>) or referenced to yet another electrical node that is not connected to earth ground nor to any of the four wires used for telephone service within the building. Any one of isolated outputs <b>308</b> and <b>309</b> of the EIC <b>304</b> can be referenced to a node within any one telecommunications device such as a subscriber line interface circuit because any current which leaves that device (including that provided by its isolated power source) on one wire of its telephone signaling pair must return to it via it the other wire of its pair.

p-0035Thus, the power conducted through the four wire network can be used to power equipment on the same four wires without interfering with the operation of those pieces of equipment, as long as each powered device is isolated from ground and from the current loop which provides the power to the input of the NID <b>302</b>.

p-0036<figref idrefs="DRAWINGS">FIG. 4</figref> shows a block diagram of another embodiment of providing DC power to a network interface device via telephone lines. The block diagram <b>400</b> includes a power supply unit (PSU) <b>470</b> with an electrical isolation component (EIC) <b>472</b> and ports <b>474</b> and <b>473</b> that couple via phone lines <b>450</b> and <b>460</b>, respectively, to a network interface device (NID) <b>402</b>. The NID <b>402</b> also includes an electric isolation component (EIC) <b>404</b> with a converter <b>406</b> and a subscriber line interface circuit (SLIC) <b>420</b>. The SLIC <b>420</b> couples to the PSU <b>470</b> via a tip wire <b>462</b> and a ring wire <b>464</b> of the phone line <b>460</b>. The SLIC <b>420</b> includes a microprocessor that couples to an isolation transformer <b>430</b>. The isolation transformer <b>430</b>, which includes multiple transformers, receives a plurality of digital signals from ground referenced logic contained in the NID <b>402</b>.

p-0037The EIC <b>404</b> of the NID <b>402</b> receives isolated DC voltage from the PSU <b>470</b> via a ring wire <b>454</b> of phone line <b>450</b> and then converts that voltage into a supplied ground referenced DC voltage <b>410</b> and at least one isolated DC voltage <b>412</b>. The EIC <b>404</b> provides isolated DC voltage to each SLIC, such as isolated DC voltage <b>412</b> being received by input <b>422</b> of the SLIC <b>420</b>.

p-0038In one embodiment, the EIC <b>472</b> of the PSU <b>470</b> generates an isolated 29V DC power supply and sends this voltage via an output port <b>474</b> across the wire <b>454</b> to an input <b>408</b> of the EIC <b>404</b>. The EIC <b>404</b> receives an isolated DC signal between 15 and 29 volts depending on the voltage drop or loss across tip wire <b>454</b>. Then, a converter <b>406</b> of EIC <b>404</b> converts the received isolated DC signal into a 12V DC ground referenced supply within plus or minus 5 percent. The converter <b>406</b> also converts the received isolated DC signal into a 12V DC isolated supply that powers the input <b>422</b> of SLIC <b>420</b>.

p-0039In another embodiment, the NID <b>402</b> includes two SLIC devices. Each SLIC device is coupled to a phone line and isolation transformer. Each SLIC device is powered with a 12V DC isolated supply received from output ports of EIC <b>404</b>.

p-0040The SLIC <b>420</b> may drive telephones, thus enabling a virtual phone line. The residential gateway provides the termination point for the feed line, which may be xDSL feed line or fiber feed line if xPON. In addition to broadband media content, it will provide the IP connection necessary for VOIP. The voice data is encoded and decoded by a processor and sent through the subscriber line interface circuit (SLIC). The SLIC provides the central office functionality to any phones connected to the phone line. The SLIC has a phone filter in front of it to provide impedance isolation and filtering. The phone filter can be a multi-order bi-directional lowpass filter. The residential gateway may optionally have other communication ports on it, such as coaxial cable or wireless. The residential gateway may optionally support HPNA networking to enable media content delivery to HPNA devices such as set top boxes within the residence.

p-0041In one embodiment, the PSU <b>470</b> plugs into 120V AC mains and generates a 29 VDC power signal that is injected onto one wire of each phone line. It is to be appreciated that other voltages would also work.

p-0042Generation of the 29 VDC power signal may be accomplished by using a rectifier connected to a power amplifier. In an embodiment, the PSU <b>470</b> generates a 29V DC signal with a current limit of 1 ampere. The power rail for the power amplifier is made from rectified and filtered line voltage that may be transformer isolated. Diodes are shown on the output and input of the PSU <b>470</b> to allow TIP and RING telephone wiring reversals at the remote outdoor location, such as NID <b>402</b>. The 29 VDC signal powers the NID <b>402</b>. The NID <b>402</b> filters and converts the 29 V DC signal to a 12V DC signal. The filtered signals of positive and negative voltage are then used to feed the multitude of switching power supply regulator circuits that are required in the residential gateway. Similarly, the 12V DC SLIC power supply is DC isolated from all other power supplies.

p-0043In one embodiment, the NID <b>470</b> has a battery. This way, the NID <b>470</b> continues to function if a brown out occurs or if a user unplugs and replugs the power module.

p-0044<figref idrefs="DRAWINGS">FIG. 5</figref> shows a method for providing DC power to a network interface device via telephone lines. The method <b>500</b> includes converting an AC power supply from a dwelling into a ground referenced DC power supply at block <b>502</b>. The method <b>500</b> further includes selecting the ground referenced DC power supply if available, otherwise selecting a battery power supply at block <b>504</b>. The method <b>500</b> further includes converting the selected power supply into an isolated DC power supply within a power supply unit at block <b>506</b>. The method <b>500</b> further includes sending the isolated DC signal from the power supply unit located in the dwelling to a network interface device (NID) located outside a dwelling via a first phone line of a first ring/tip pair at block <b>508</b>. The method <b>500</b> further includes returning the isolated DC signal from the NID to the power supply unit via a second phone line of a second ring/tip pair at block <b>510</b>. The method <b>500</b> further includes converting the isolated DC power supply into a ground referenced DC power supply and at least one isolated DC power supply within the NID at block <b>512</b>. The ground referenced DC power supply provides power to NID components not requiring isolated power. Each isolated DC power supply of the NID provides power to a subscriber line interface circuit (SLIC) that drives one phone line.

p-0045In one embodiment, because current leaves the power supply unit on one wire of the first phone line and returns on one wire of the second phone line, each telephone wire pair experiences no imposed current between the two wires which comprise one telephone pair. An imposed voltage of less than 5V may develop which depends on the length of the two wires. Subscriber line interface circuits that use the two wires can be made to compensate or null out the imposed voltage so as to not effect operation. For the same reason, no electrical impedance change is perceivable between the wires of any one telephone pair; allowing telephone use on each pair to proceed as if the power distribution scheme was not present. The first and second phone lines provide two voice circuits in the dwelling and simultaneously provide a power circuit for the NID.

p-0046Overall, the use of one wire from each telephone line to supply power to a remote communications device maintains the present signal to noise ratios on those lines without increasing the noise. Further, cross talk between the two discreet pairs is not significantly affected. Also, extra electro magnetic interference is not generated nor do violations of GR-1089 AC signal levels occur.

p-0047Although the operations of the method(s) herein are shown and described in a particular order, the order of the operations of each method may be altered so that certain operations may be performed in an inverse order or so that certain operation may be performed, at least in part, concurrently with other operations. In another embodiment, instructions or sub-operations of distinct operations may be in an intermittent and/or alternating manner.

p-0048Thus, according to embodiments of the present invention, systems and methods for providing DC power to a network interface device via telephone lines are described. The systems and methods enable a first phone line and a second phone line to provide two voice circuits in the dwelling and simultaneously provide a power circuit for the network interface device located outside a dwelling without needing separate wiring to power the network interface device.

p-0049While some specific embodiments of the invention have been shown the invention is not to be limited to these embodiments. For example, most functions performed by electronic hardware components may be duplicated by software emulation. Thus, a software program written to accomplish those same functions may emulate the functionality of the hardware components. The hardware logic may consist of electronic circuits that follow the rules of Boolean Logic, software that contain patterns of instructions, or any combination of both. The invention is to be understood as not limited by the specific embodiments described herein, but only by scope of the appended claims.